COVAX aims to deliver over two billion coronavirus vaccine doses to 190 countries this year.
Its first batch was delivered in late February, with lower-income countries receiving their first vaccines.
Controversially, Canada will receive a batch, despite ordering five times more doses than it needs. It has been among the slowest of the developed nations to inoculate its citizens.
COVAX will distribute vaccines to countries in proportion to their population. It expects to reach 3.3 percent of the population of the 145 facility participants during the first phase, with vaccines given to the most vulnerable populations, including healthcare workers.
Countries will progressively receive doses until all reach 20 percent of their population, moving on to the second phase once all countries have done so. Recipients will receive doses based on considerations of vulnerability and COVID-19 risk.
Phase one should be complete by the middle of the year.